Customers who have downloaded Square's Wallet app on iPhones or Android smartphones will be able to buy coffee by presenting a barcode the app generates for scanning at a Starbucks cash register. Some of Square's advanced features, which let a customer open a tab in a store on the app and pay by saying their name, won't be available at launch.

Square has also said it will begin processing regular credit- and debit-card transactions—those old-fashioned sales where you swipe a plastic card—for Starbucks as well. It's not clear if this part of the deal is launching at the same time as the mobile-payments feature.

When the deal was announced, Square said Starbucks stores would be listed in a directory of Square merchants that appears in its app and on Square's website. Starbucks' listing in the directory went live late Thursday evening.

Here's the press release:

Starbucks Offers Square Wallet Beginning Today

Starbucks extends mobile payment choice and convenience to its customers at participating U.S. stores

With Square Wallet people can pay at Starbucks and explore nearby businesses, browse menu information, store hours and transaction history, all on their phone. Square Wallet is in addition to Starbucks own mobile payment applications on iOS and Android™, which are used by Starbucks customers more than 2 million times each week, and are fully integrated with the Starbucks Card and My Starbucks Rewards™ programs.

“We look forward to continuing to create amazing connections with our customers – both in our stores and outside of our stores and offering our customers choices in how they want to pay. Starbucks was the first national retailer to offer its own mobile payment technology combined with a world-class loyalty program in January 2011, and we have seen a tremendous response from our customers with more than 100 million mobile transactions occurring in our U.S. stores since its launch,” said Adam Brotman, Starbucks chief digital officer. “Starbucks believes in the values and vision of Square, and just three months after announcing our partnership with Square, we are thrilled to make the convenience of paying with the Square Wallet app available to our customers starting today.”

Customers simply download Square Wallet to their iOS or Android™ device to set up an account. SquareWallet is linked to their debit or credit card, so there is never a need to reload a balance. Customers tap “pay here” and scan their QR code – similar to the customer experience on the existing Starbucks mobile payment applications. Their digital receipt appears instantly.

“Square Wallet gives people an easy way to pay at Starbucks and neighborhood businesses,” said William Henderson, Square Wallet director. “We’re excited to work with Starbucks to introduce a broad new group of people to the benefits of using Square."

The Starbucks Digital Network in Starbucks stores will feature the Square directory so customers can discover neighborhood businesses near their favorite Starbucks store.

Note: Customers should be running iOS 5.0 or above or Android 2.2 or above on their mobile device to be able to use Square Wallet. Customers can learn more at http://www.starbucks.com/squarewallet.